Packaging tray

ABSTRACT

A molded plastic tray adapted to receive a plastic overwrap film for preservation, secure handling and display of a perishable food product in the wrapped tray, such as fresh fruit or vegetables. The tray has a pair of central ribbing elements extending from opposing longitudinal side walls and into the bottom wall and is designed to provide structural rigidity that resists warping and collapse, thus enabling the overwrapped tray to be handled, shipped, and displayed with minimal leakage while preserving the food product therein. The tray is easy to manufacture and provides a lightweight and cost effective packaging product. The tray has a rectangular shape that provides for consistent wrapping strength and can be handled on standard processing equipment.

FIELD OF THE INVENTION

The invention relates to a plastic packaging tray and, more particularly, to a molded plastic overwrap tray for secure packaging and preservation of a food product such as fresh fruit or vegetables.

BACKGROUND OF THE INVENTION

Various plastic trays for packaging food, such as fresh fruit and vegetables, are known in the prior art. In designing such a tray, inner surface area, capacity, sidewall rigidity, and weight are key considerations. These trays are typically packed with perishable food items and then surrounded with a plastic film overwrap to both display and seal the food within the package. During the filling, conveying and wrapping processes, the trays are subjected to applied external forces (e.g., by automated equipment) that can warp or damage the tray, leading to a misalignment or malfunction on the processing line, bruising or other damage to the fresh food product, and/or irregularly filled trays. In particular, the tray may twist or collapse inwardly due to forces applied during wrapping and handling. Once wrapped the tray is ready to be placed in a container for shipment; typically, multiple wrapped trays are fit into standard sized cases and then stacked one upon another and the weight of the packaged trays may cause the plastic film of underlying trays to be stretched and loosened during shipment. As a result the wrapped trays may leak juices from the products packaged therein, leading to a loss of aesthetic appeal, loss of shelf life, contamination of adjacent packages, and difficulty in handling.

It would be desirable to provide such a plastic packaging tray that can be wrapped (while filled) with a plastic film, where the film is maintained in a taut state about the filled tray during shipping and handling.

It would be desirable to provide such a tray having substantial structural rigidity.

It would be desirable to provide such a tray that is easy and inexpensive to manufacture, easy to load (fill with product), and easy to handle on automated equipment.

It would be desirable to provide such a tray that can safely and securely package fresh fruit and vegetables without bruising or otherwise damaging the fruit or vegetable.

SUMMARY OF THE INVENTION

A molded plastic tray is provided according to the invention adapted to receive a plastic overwrap film for preservation, secure handling and/or display of a product in the wrapped tray, such as a fresh fruit or vegetable. The tray is designed to provide structural rigidity that resists warping or collapse, thus enabling the overwrapped tray to be handled, shipped, and displayed with minimal leakage and while preserving the food product therein. In some embodiments the tray includes features that facilitate de-nesting of a stack of empty trays, and is adapted to facilitate movement of the wrapped package on a moving conveyor line. The tray is easy to manufacture and provides a lightweight and cost effective packaging product. Preferably the tray has a rectangular shape that provides for consistent wrapping strength and can be handled on standard processing equipment.

In one embodiment, a molded plastic packaging tray is provided for receiving a perishable food product and wrapping in a plastic film wrap to preserve the food product, the packaging tray comprising:

-   -   an integral molded plastic tray having topside and underside         surfaces, the underside surface including a lowermost standing         surface of the tray;     -   the topside surface defining a flange having a rectangular         perimeter lying in a top reference plane TRP, the rectangular         perimeter comprising opposing first and second longitudinal         edges aligned parallel to a longitudinal centerline LCL of the         tray, opposing first and second lateral edges aligned parallel         to a transverse centerline TCL that is transverse to the LCL,         and rounded corner edges joining the side edges and lateral         edges;     -   the tray topside surface defining a recessed cavity wall         depending downwardly from the rectangular perimeter to define an         interior cavity having an open top end, the interior cavity         comprising a substantially flat bottom wall, and extending         upwardly from the bottom wall toward the flange, a pair of         opposing longitudinal side walls disposed parallel to and         equidistant from opposing sides of the LCL, a pair of opposing         end walls disposed parallel to and equidistant from opposing         sides of the TCL, and four rounded corner walls joining the side         walls and end walls and which collectively, with the bottom         wall, form the interior cavity;     -   a pair of central ribbing elements, each ribbing element forming         an arc that lies in the TCL and extending into a respective side         wall and the bottom wall so as to prevent outward sagging of the         tray in the LCL direction, as well as preventing inward         collapsing of the tray in the TCL direction, when the tray is         filled with a product and the filled tray is wrapped in a         plastic film wrap.

In another embodiment, a method of packaging a perishable food product is provided comprising:

-   -   depositing a perishable food product into the interior cavity of         the molded plastic packaging tray;     -   providing a sheet of wrapping film and positioning it over the         tray and the food product deposited therein;     -   pulling the sheet taut to engage the surface of the food product         deposited within the tray and the rectangular flange perimeter;         and     -   securing the sheet to the tray.

In one embodiment, the tray includes:

-   -   a trim area extending from upper end portions of the side walls,         end walls and corner walls of the interior cavity, the trim area         including the flange;     -   the flange comprising a top surface lying within the TRP and         including opposing inner and outer edges.

In one embodiment:

-   -   the outer edge of the flange is coextensive with the rectangular         perimeter; and     -   a trim lip extends from the outer edge downwardly away from the         TRP for strengthening the trim area.

In one embodiment, the trim lip has an exterior edge that forms a substantially rectangular perimeter.

In one embodiment, the arc extends between first and second ends, the first end extending from the respective side wall or an adjacent trim area at the open top end of the cavity, and the second end extending from the bottom wall.

In one embodiment, the arc of the ribbing element comprises an arc shaped upper surface that extends between the first and second ends, and opposing side walls that extend downwardly away from the TRP from opposite sides of the upper surface between the first and second ends.

In one embodiment, the bottom wall includes a flat gap extending between the second ends of the respective arcs.

In one embodiment, the flat gap extends across 25-35% of a width of the bottom wall in the TCL direction, and more preferably 25-30%.

In one embodiment, each arc extends across 25-40% of a width of the bottom wall in the TCL direction, and more preferably 35-40%.

In one embodiment, the interior cavity has a height extending from the bottom wall to the TRP and transverse to the TRP, and each arc has a height transverse to the TRP of 75-100% of the cavity height, and more preferably 80-95%.

In one embodiment, the tray has a length L in the LCL direction and a width W in the TCL direction, and the ratio of L:W is greater than 1.25.

In one embodiment, the ratio of L:W is in a range from 1.25 to 2, and more preferably in a range from 1.5 to 2.

In one embodiment, the molded tray is made of a plastic material comprising one or more of polyester and polyolefin material, including homo-polymers, copolymers, mixtures and blends of the material, including foam and non-foam material, and including virgin and reclaimed and recycled material.

In one embodiment, the plastic material comprises polyethylene terephthalate material.

In one embodiment, the cavity wall depends downwardly from the TRP at an acute angle.

These and other features of the invention will be better understood from the following detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective view of a filled and wrapped tray for preserving and displaying a product (here fresh mushrooms) and having a pair of central ribbing elements according to a first embodiment of the invention.

FIG. 2 is a top perspective view of the empty tray of FIG. 1 (prior to filling and wrapping) disclosing: a) a partial view of an interior cavity showing one of the central ribbing elements extending into the cavity from one elongated side wall, and b) a partial exterior view of the other central ribbing element extending into the opposing elongated side wall.

FIG. 3 is a side elevational view of the tray of FIG. 2, showing an exterior view of one of the central ribbing elements.

FIG. 4 is a lateral end elevational view of the tray of FIG. 2.

FIG. 5 is a top plan view of the tray of FIG. 2 showing the entire interior cavity with the opposing central ribbing elements each extending inwardly from opposing elongated side walls and inwardly from the bottom wall of the tray.

FIG. 6 is a transverse cross-sectional interior view of the tray of FIG. 2 taken along section line 5-5 in FIG. 5.

FIG. 7 is a top partial perspective view of the tray of FIG. 2 showing the interior of an upper cavity portion which includes an upper end of one central ribbing element and the adjacent trim area.

FIG. 8 is a top partial perspective view, similar to FIG. 7, but showing the lower end of the one central ribbing element extending into the bottom wall.

DETAILED DESCRIPTION OF THE INVENTION

Referring generally to FIGS. 1-8, a first embodiment of a plastic tray of the invention is depicted therein and generally designated with the numeral 10. FIG. 1 shows the tray 10 filled with a product P, here a predetermined amount (e.g., by weight or volume) of fresh whole mushrooms, which is then wrapped with a clear plastic film F (overwrap) to contain, preserve and display the product within the wrapped package 11. FIGS. 2-8 show the empty tray 10, prior to filling and wrapping, providing interior and exterior views of the tray having a pair of opposing central ribbing elements 40 a, 40 b according to one embodiment of the invention. The tray with central ribbing elements provides a desired combination of strength and rigidity in a light weight molded plastic tray that is easy to manufacture, fill, handle and wrap. These advantages will be described further below.

In forming the tray 10 it is preferred that the tray be unitarily formed from a single sheet of plastic material to define the features described herein. In the present embodiment the thickness of the tray is substantially equal throughout. However, during manufacturing the plastic material will often compress differently at various locations, resulting in some thickness variations in the tray (for example thickness variations in the corners, base, trim area or recessed wall portions). The tray may be made of any of various known thermoplastic and thermoset plastic materials. In various embodiments, the tray is made of polyethylene terephthalate (PET) material, including foam and non-foam PET material, and including virgin and reclaimed and recycled PET material.

As shown in FIG. 2, the tray 10 has been molded (by application of heat and pressure from a sheet of moldable plastic material) to form on a topside 62 of the molded sheet a recessed interior cavity 60 for holding the product P, and on the opposing underside 72 a base 12 with feet 76 (see FIG. 6) that form an exterior standing surface on which the tray is designed to lie substantially flat on a planar resting surface (such as a packing case or store display). The embodiment shown is formed from molding procedures which utilize matched mating male and female dies. The molded tray has opposing inner (topside) and outer (underside) surfaces 62, 72 that form the various shaped elements of the tray and are shown (in FIG. 6) to be generally parallel. The tray however may be formed with various portions which do not have parallel inner and outer surfaces.

As best shown in FIGS. 2 and 5, the interior cavity 60 includes a substantially flat (planar) bottom wall 13, and extending upwardly from the bottom wall, a pair of opposing elongated longitudinal side walls 14, 16, a pair of opposing lateral end walls 18, 20 and four rounded corner walls 22, 24, 26, 28 joining the side walls and end walls and which collectively (with the bottom wall) form the interior cavity. Additionally, the tray 10 may be lined or coated with barrier film. A top flange 30 (part of an upper trim area TA) is provided at the open top end of the tray, the flange having a planar top wall 31 lying in a top reference plane TRP and extending outwardly from upper (top end) portions of the side walls 14, 16, end walls 18, 20, and corner walls 22, 24, 26, 28. In this embodiment, the TRP lies substantially parallel to a base reference plane (BRP) in which an interior surface of the flat bottom wall 13 resides (see FIG. 4).

As best shown in FIG. 5, the tray 10 has a generally rectangular shape in a plane parallel to the TRP. The rectangular shape of the tray is defined (see FIG. 5) with respect to: a) a longitudinal center line (LCL) disposed half way between the opposing side walls 14, 16, each of the side walls along with their adjacent corner walls and trim area collectively having a length L in a longitudinal direction parallel to the LCL, and 2) a transverse center line (TCL) perpendicular to the LCL and disposed half way between the opposing end walls 18, 20, each of the end walls along with their adjacent corner walls and trim area collectively having a width W in a transverse direction parallel to the TCL. It is preferable that the side walls 14, 16 and end walls 18, 20 of the tray have at their uppermost ends a trim area TA with substantially straight (linear) edges, here formed by the straight edges of the top wall 31 (of flange 30 and lying in the TRP) for improved wrapping capability, while the uppermost ends of the corner walls 22, 24, 26, 28 comprise rounded corners of the top wall 31 to avoid undue stress on the wrapping film.

As shown in FIG. 5-7, the top wall 31 of the upper flange 30 has an inner rectangular periphery 30RP-inner with rounded corners that lies in or parallel to the TRP, and an outer rectangular periphery 30RP-outer with rounded corners that lies in or parallel to the TRP. The tray has a flat bottom wall 13 having a rectangular periphery 13RP with rounded corners that lies in the BRP. The rectangular periphery 13RP of the bottom wall 13 has a length LBW in the LCL direction and a width WBW in the TCL direction. The side walls 14, 16, end walls 18, 20 and the four corner walls 22, 24, 26, 28 extend between the bottom wall periphery 13RP and the inner flange periphery 30RP-inner (or to a lip area adjacent to 30RP-inner). The trim area TA, including the flange, may include one or more reinforcing elements 32 (e.g., shoulders, recesses or grooved edge portions as shown in FIG. 7) to further reinforce the trim area and flange, and the side walls 14, 16, end walls, 18, 20 and/or the four corner walls 22, 24, 26, 28 may also include one of more reinforcing elements 33 (e.g., shoulders, posts, recesses or grooved edge portions as shown in FIGS. 2 and 7) to further reinforce the walls. These reinforcing elements may or not be present in various embodiments of the present invention.

As previously described, the tray forms an interior cavity 60 defined by the inner surfaces of the side walls, end walls, corner walls and bottom wall. This cavity is further formed, in accordance with one embodiment of the invention, with a pair of central ribbing elements 40 a and 40 b, shown in transverse cross section in FIG. 6, each ribbing element having a top wall forming an arc 43 that lies in the TCL and opposing ribbing side walls 45, 46 extending from the top wall 43 into a respective side wall 14, 16 and into the bottom wall 13 so as to prevent outward sagging of the tray in the LCL direction, as well as preventing inward collapsing of the tray in the TCL, especially during the wrapping process. The center ribbing elements further strengthen the tray by extending (at their upper end 41) into the top trim area (TA), or adjacent thereto, while also extending (at their lower end 42) into and across a substantial portion of the bottom wall to strengthen the flat planar bottom wall 13. The bottom wall includes a central flat gap area 13 g having a width Wgap extending between the second ends 42, 42 of the opposing ribbing elements 40 a, 40 b. This gap further strengthens the bottom wall, and they tray against collapse.

As best shown in FIGS. 5 and 7-8, each ribbing element 40 a, 40 b has opposing ribbing side walls 45, 46 that extend, from opposing edges 43 e 1, 43 e 2 of the upper arced surface 43 respectively, to an interior surface of a respective side wall 14 or 16, and to an interior surface of the flat bottom wall 13. The ribbing side walls 45, 46 lie in one or more planes transverse to the BRP or tapered at an angle (e.g., 60-90 degrees) to the BRP, to provide rigidity and strength to the overall tray and retard or prevent twisting, collapse or sagging of the tray in any direction. The opposing ribbing side walls 45, 46 are joined to each other at opposing first and second ends 41. 42 of the ribbing element 40, by rounded contours 41C and 42C, respectively, and to opposing edges 43 e 1 and 43 e 2 of the arced top surface 43 by rounded contours 45C, 46C to reduce potential stress concentration points that may lead to cracking of the tray at these points (see FIGS. 7-8).

In various embodiments, each ribbing element 40 a, 40 b has an overall height RH transverse to the TRP and width RW parallel to the TRP (see FIG. 6), wherein RH ranges from 90-100% of the distance between the TRP and BRP (and more preferably 95-100% or 98-100%), and RW ranges from 30-50% of the distance between the second end 42 and the opposing outermost edge 30RP-outer of the top flange 30 lying in the TRP (and more preferably 35-45% or 40-45%). The cavity height CH as shown in FIGS. 6 and 3-4, is defined as the distance between the TRP and BRP.

In the present embodiment, the side walls 14, 16 and end walls 18, 20 are angularly disposed relative to the top reference plane TRP to define an acute angle α relative to a transverse axis A which is perpendicular to the TRP (see FIGS. 3-4). The angle α is preferably in a range of 5° to 15°, and more preferably 7° to 12°. The corners 22, 24, 26, 28 are also angularly disposed relative to the TRP. Preferably, each of the corners is generated by rotating a plane curve about a central reference axis which is perpendicular to the TRP. The corners 22-28 are preferably formed to define an acute angle beta relative to the central reference axis in the range of 7 to 20°. A representative corner 28 (see FIG. 6) is formed with a rounded inner surface 62C, a rounded outer surface 72C, and a planar top surface 31C.

A shoulder 32 (FIG. 7) or other de-nesting element may be provided that extends inwardly from the side walls, end walls and/or corner walls, typically in the trim area right below the flange 30. The shoulder may be continuous or formed with interruptions and may be formed with an arcuate or sloped shape as shown. The shoulder assists in spaced stacking of empty trays, wherein the top surface of the flange 30 of a lower tray 10 is spaced a distance from the top surface of the flange 30 of an upper tray 10. This spacing facilitates de-nesting of empty stacked trays.

The flange 30 in the present embodiment lies in a top reference plane (TRP) substantially parallel to the base reference plane (BRP). In other embodiments, the flange may be inclined upwardly or downwardly with respect to the BRP. In the present embodiment, the trim area TA has an outer lip 35 extending downwardly (toward the BRP) from the top wall 31 of the flange so as to evenly distribute the tension in the plastic film wrapped around the loaded tray.

Referring again to FIG. 1, there is shown a tray 10 filled with product P, here a plurality of fresh whole mushrooms, and the filled tray 11 being tightly wrapped (taut) in a plastic film F (shown to be transparent) that surrounds the entire filled tray. The flange 30 along the side walls, end walls and corner walls apply force to the film F to maintain tautness. The wrapping film may somewhat deflect the flange 30 from its original molded shape, however the central ribbing elements 40 a, 40 b maintain the overall rectangular perimeter of the filled tray in the wrapped state. With the plastic film F being maintained in a taut state, the trays of the present invention can be filled, wrapped and stacked in a master container for shipment. With an upper wrapped tray or case resting on the plastic film F of a lower wrapped tray, although the plastic F of the lower tray may stretch slightly, the plastic film F remains taut and does not become loosened about the tray. The same result is achieved even where the packaged goods P extend above the tray as shown in FIG. 1.

The tray 10 comprising the present invention may vary in size for storage and display of products that vary in size and weight. The tray of the present embodiment has dimensions of about 11 inches in length L, 7 inches in width W, and 3 inches in height H, and the bottom wall has a length of about 7 inches and a width of about 3 inches. It is to be realized that the optimum dimensions of various parts of the tray will vary in size, materials, shape, and form that are deemed readily apparent and obvious to one skilled in the art. The present embodiment is intended to be just one example of the invention and not limiting.

As is readily apparent, numerous modifications and changes may readily occur to the skilled person in the art, and hence it is not desired to limit the invention to the exact construction and operation as shown and described. All suitable modifications and equivalents may be considered to fall within the scope of the invention as claimed. 

What is claimed is:
 1. A molded plastic packaging tray for receiving a perishable food product and wrapping in a plastic film wrap to preserve the food product, the packaging tray comprising: an integral molded plastic tray having topside and underside surfaces, the underside surface including a lowermost standing surface of the tray; the topside surface defining a flange having a rectangular perimeter lying in a top reference plane TRP, the rectangular perimeter comprising opposing first and second longitudinal edges aligned parallel to a longitudinal centerline LCL of the tray, opposing first and second lateral edges aligned parallel to a transverse centerline TCL that is transverse to the LCL, and rounded corner edges joining the side edges and lateral edges; the tray topside surface defining a recessed cavity wall depending downwardly from the rectangular perimeter to define an interior cavity having an open top end, the interior cavity comprising a substantially flat bottom wall, and extending upwardly from the bottom wall toward the flange, a pair of opposing longitudinal side walls disposed parallel to and equidistant from opposing sides of the LCL, a pair of opposing end walls disposed parallel to and equidistant from opposing sides of the TCL, and four rounded corner walls joining the side walls and end walls and which collectively, with the bottom wall, form the interior cavity; a pair of central ribbing elements, each ribbing element forming an arc that lies in the TCL and extending into a respective side wall and the bottom wall so as to prevent outward sagging of the tray in the LCL direction, as well as preventing inward collapsing of the tray in the TCL direction, when the tray is filled with a product and the filled tray is wrapped in a plastic film wrap.
 2. A method of packaging a perishable food product comprising: depositing a perishable food product into the interior cavity of the molded plastic packaging tray of claim 1; providing a sheet of wrapping film and positioning it over the tray and the food product deposited therein; pulling the sheet taut to engage the surface of the food product deposited within the tray and the rectangular flange perimeter; and securing the sheet to the tray.
 3. The tray of claim 1, wherein the tray includes: a trim area extending from upper end portions of the side walls, end walls and corner walls of the interior cavity, the trim area including the flange; the flange comprising a top surface lying within the TRP and including opposing inner and outer edges.
 4. The tray of claim 3, wherein: the outer edge of the flange is coextensive with the rectangular perimeter; and a trim lip extends from the outer edge downwardly away from the TRP for strengthening the trim area.
 5. The tray of claim 4, wherein the trim lip has an exterior edge that forms a substantially rectangular perimeter.
 6. The tray of claim 1, wherein the arc is extends between first and second ends, the first end extending from the respective side wall or an adjacent trim area at the open top end of the cavity, and the second end extending from the bottom wall.
 7. The tray of claim 6, wherein the arc of the ribbing element comprises an arc shaped upper surface that extends between the first and second ends, and opposing side walls that extend downwardly away from the TRP from opposite sides of the upper surface between the first and second ends.
 8. The tray of claim 7, wherein the bottom wall includes a flat gap extending between the second ends of the respective arcs.
 9. The tray of claim 8, wherein the flat gap extends across 25-35% of a width of the bottom wall in the TCL direction, and more preferably 25-30%.
 10. The tray of claim 1, wherein: each arc extends across 25-40% of a width of the bottom wall in the TCL direction, and more preferably 35-40%.
 11. The tray of claim 10, wherein the interior cavity has a height extending from the bottom wall to the TRP and transverse to the TRP, and each arc has a height transverse to the TRP of 75-100% of the cavity height, and more preferably 80-95%.
 12. The tray of claim 1, wherein the tray has a length L in the LCL direction and a width W in the TCL direction, and the ratio of L:W is greater than 1.25.
 13. The tray of claim 12, wherein the ratio of L:W is in a range from 1.25 to 2, and more preferably in a range from 1.5 to
 2. 14. The tray of claim 1, wherein the molded tray is made of a plastic material comprising one or more of polyester and polyolefin material, including homo-polymers, copolymers, mixtures and blends of the material, including foam and non-foam material, and including virgin and reclaimed and recycled material.
 15. The tray of claim 11, wherein the plastic material comprises polyethylene terephthalate material.
 16. The tray of claim 6, wherein the cavity wall depends downwardly from the TRP at an acute angle. 